In the latest case, Safari challenged the Federal Aviation Administration's move in 2000 to extend the original SFAR 71 for three more years, arguing that the rule actually decreases aviation safety and increases the risk of predictable accident scenarios.

The appeals court said that as a matter of law, the court may not set aside an agency's action unless it is "arbitrary, capricious, an abuse of discretion or otherwise not in accordance with law."

Safari's attorney, David Bettencourt, could not be reached immediately for comment.

In support of its 1994 rule, the FAA noted that between 1982 and 1991, during a nine-year period of substantial growth in the tour industry, there were eight air tour accidents in Hawaii resulting in 24 deaths. It noted in the following three years through July 1994, there were 20 air tour accidents and 24 deaths.

In the challenge to extending the rule for three years, the 9th U.S. Circuit Court in San Francisco ruled yesterday that the FAA had a rational basis for the rule and had not denied Safari an opportunity to participate in the rule-making process.

The court noted that the FAA worked closely with the air tour operators to allow deviation from the rule on a case-by-case basis and has granted deviations to a majority of the air tour operators.

For instance, air tour operators of single-engine helicopters have been granted deviations to conduct air tours at a minimum of 500 feet in specific areas, the court said.

Safari argued that the minimum altitude didn't account for prevailing weather conditions, would concentrate aircraft at the same altitude and create hazardous conditions for emergency landings.

The company suggested that because the FAA didn't detail the circumstances under which it grants or does not grand the altitude deviations, the practice itself may constitute unlawful rule-making.

The appeals court disagreed, saying the deviations are allowed as interpretative rules that are not subject to the rule-making requirements because they only clarify or explain existing law or regulations.

"By granting the deviations, the FAA has provided the majority of Hawaii air tour operators with specific interpretations of how SFAR 71's minimum altitude requirement applies to them in light of their individual safety qualifications and differences in local terrain and prevailing conditions," the court said.

"This is another rational reason the FAA has provided to explain why the safety related criticism of SFAR 71 have been mitigated since the rule's enactment."